# Slamon 1989: HER2/neu in human breast and ovarian cancer

Source: https://onco.cc/key-papers/paper-slamon-her2-breast-ovarian-science-1989/  
OnCo record `paper-slamon-her2-breast-ovarian-science-1989` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

The follow-up to the 1987 discovery: extra copies of the HER2 gene were found in about a quarter to a third of breast cancers and also in ovarian cancers, they led to overproduction of the HER2 protein, and they marked patients with worse outcomes in both diseases.

## Summary

Slamon and colleagues examined HER2/neu gene amplification and expression in 526 breast cancers and 120 ovarian cancers. Amplification was present in about a quarter to a third of the breast tumours and was tightly linked to overexpression of HER2 messenger RNA and protein, so measuring the protein could stand in for measuring the gene. Amplification and overexpression were associated with poorer survival in breast cancer and, for the first time, were shown in ovarian cancer with a similar prognostic effect.

## Fields

- Kind: Key paper
- Last checked: 2026-09-08
- Journal: Science
- Year: 1989
- DOI: 10.1126/science.2470152
- Authors: Slamon DJ, Godolphin W, Jones LA, et al.
- Findings: HER2/neu amplification in about 25 to 30% of 526 breast cancers, correlating with mRNA and protein overexpression.; HER2 amplification and overexpression also found in ovarian cancers, associated with poorer survival.; Protein overexpression by immunohistochemistry tracked gene amplification, supporting a tissue test.
- What it means: This study confirmed HER2 as a prognostic marker and a therapeutic target, showed that immunohistochemistry could identify the patients, and extended the target to ovarian cancer. It set up the clinical development of trastuzumab and the HER2 testing that every breast cancer now receives.
- Caveats: Retrospective tumour bank study.; Ovarian findings were smaller in scale and HER2-directed therapy has had less success in ovarian cancer than in breast cancer.

## Sources

- Full text (DOI): https://doi.org/10.1126/science.2470152

## Connected records

- key papers: [Slamon 1987: HER2 gene amplification marks an aggressive form of breast cancer](https://onco.cc/key-papers/paper-slamon-her2-amplification-science-1987/), [Slamon 2001: adding trastuzumab to chemotherapy for HER2-positive metastatic breast cancer](https://onco.cc/key-papers/paper-slamon-trastuzumab-nejm-2001/)
- cancers: [HER2-positive breast cancer](https://onco.cc/cancers/breast-her2-positive/), [Ovarian cancer](https://onco.cc/cancers/ovarian/)
- targets: [HER2](https://onco.cc/targets/her2/)
- institutions: [UCLA Jonsson Comprehensive Cancer Center](https://onco.cc/institutions/ucla-jonsson/)
- people: [Dennis J. Slamon](https://onco.cc/people/dennis-slamon/)
- ideas: [Deliver CAR-T cells straight into the fluid around the brain](https://onco.cc/ideas/idea-bio2-intraventricular-car-t/), [Re-map the tumour's surface proteins before choosing the next antibody drug](https://onco.cc/ideas/idea-bio1-antigen-mapping-at-progression/), [Use the brain's own transport door to carry antibody drugs across](https://onco.cc/ideas/idea-bio2-transferrin-shuttle-adc/)

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